The present invention is concerned with an artificial capillary cell culture device. More particularly, the present invention relates to an artificial capillary cell culture device having improved features which include the incorporation into a single bundle of ultrafiltration fibers connected to two separate perfusion circuits and the interweaving of fibers to maintain intimate contact. The artificial capillary device of the present invention provides a matrix for high density growth of cultured cells in a continuous perfusion system.
Previous artificial capillary cell culture devices have included the device described in U.S. Pat. No. 3,883,393 to Knazek, et al., in which there is provided a bundle of unwoven hollow fibers connected to a single perfusion circuit. In such devices, in which the fibers are laid out parallel to one another during construction of the bundle, there are three main problems which are inherent. One problem is that the fibers may splay apart from one another when the bundle is sealed in the shell, increasing the possibility that cells between fibers may be anoxic, thus preventing the formation of a continuous tissue-like cell mass on the fiber bundle. A second main problem resides in the fact that the fibers may dry and contract following humidified ethylene oxide sterilization of the device, one result being that breakage may occur more easily in individual fibers. A third problem concerns distribution of nutrients which occurs simply by diffusion in the previous device.
By the present invention, there is provided an artificial capillary cell culture device which has overcome the difficulties described in connection with previous cell culture devices such as that of U.S. Pat. No. 3,883,393. The cell culture device of the present invention has features which include the incorporation into a single woven bundle of ultrafiltration fibers, with a portion of the fibers being connected to one perfusion circuit and the remaining fibers being connected to a second perfusion circuit. A difference in pressure between the two circuits produces convective currents of perfusate within the extracapillary space and improves nutrient distribution. Thus the present device is provided with two separate perfusion circuits which feed a single culture unit, but with the fibers associated with the separate circuits being in intimate contact with one another in a woven configuration. The present construction permits observation of mass transfer of chemical species from one perfusion circuit into another through the cell mass. In addition, the present device provides for induction of fluid filtration between perfusion circuits to simulate processes such as lymphatic drainage of the cell mass.
The woven construction of the present fiber bundle results in a fiber bundle which is coherent and yet compliant, with the fibers from the separate circuits being in intimate contact. In addition, while the weaving of the fiber bundle provides structural strength, at the same time the bundle is sufficiently flexible to absorb possible contractions or displacements caused by the imposition of fluid pressure differences required to employ the device in processes such as inducing simulated lymphatic drainage.